kapi: rework text device interface

2 files changed, 29 insertions, 17 deletions

diff --git a/kapi/include/kapi/cio.hpp b/kapi/include/kapi/cio.hpp
new file mode 100644
index 0000000..6b93638
--- /dev/null
+++ b/kapi/include/kapi/cio.hpp
@@ -0,0 +1,29 @@
+#ifndef TEACHOS_KAPI_IO_HPP
+#define TEACHOS_KAPI_IO_HPP
+
+#include <optional>
+#include <string_view>
+
+namespace teachos::cio
+{
+  struct output_device
+  {
+    auto virtual write(std::string_view text [[maybe_unused]]) -> void {}
+    auto virtual writeln(std::string_view text [[maybe_unused]]) -> void {}
+
+    auto virtual write_error(std::string_view text [[maybe_unused]]) -> void {}
+    auto virtual writeln_error(std::string_view text [[maybe_unused]]) -> void {}
+  };
+
+  auto init() -> void;
+
+  auto set_output_device(output_device & device) -> std::optional<output_device *>;
+
+  auto print(std::string_view text) -> void;
+  auto println(std::string_view text) -> void;
+
+  auto print_error(std::string_view text) -> void;
+  auto println_error(std::string_view text) -> void;
+}  // namespace teachos::cio
+
+#endif
diff --git a/kapi/include/kapi/io.hpp b/kapi/include/kapi/io.hpp
deleted file mode 100644
index 764738f..0000000
--- a/kapi/include/kapi/io.hpp
+++ /dev/null
@@ -1,17 +0,0 @@
-#ifndef TEACHOS_KAPI_IO_HPP
-#define TEACHOS_KAPI_IO_HPP
-
-#include <string_view>
-
-namespace teachos::io
-{
-  auto init() -> void;
-
-  auto print(std::string_view text) -> void;
-  auto println(std::string_view text) -> void;
-
-  auto print_error(std::string_view text) -> void;
-  auto println_error(std::string_view text) -> void;
-}  // namespace teachos::io
-
-#endif